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  • repair/recovery tool for Western Digital Elements (1TB)

    - by Pennf0lio
    My Hard Disk Drive just got corrupted due to electricity fluctuation. When I plug my Western Digital Elements, It ask me if I want to format it or not... I can't see my files or even the capacity of my disk from it's properties. Is there any solution you would suggest? looking for a software that can give me access to my files. I just need to copy it then I can retire my Drive and will buy a new one... Thanks!

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  • Strange Lose Of Format On Pen Drive

    - by Kiewic
    Hi, here is an screenshot of my pen drive. The files are impossible to open, and the names has been replaced by strange characters. In Ubuntu is worst, the windows system crash. What can I do to recover my information?

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  • hard drive sectors vs. tracks

    - by Phenom
    In one rotation, how many sectors are passed over and how many tracks are passed over? If you know the average value of sectors per track for a hard drive, how do you use this to estimate the number of cylinders? Do all modern hard drives have 63 sectors per track? Are there any hard drives that have more than this?

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  • Strange loss of format on pen drive

    - by Kiewic
    Hi, here is an screenshot of my pen drive. The files are impossible to open, and the names have been replaced by strange characters. In Ubuntu is worst, the Windows system crash. What can I do to recover my information?

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  • HDD dead forever???

    - by Roberto
    Yesterday I turned on my computer and it couldn't boot. I found out the hd (320GB SATA Seagate Momentus 7200.3 for notebook) was broken, it couldn't be recognized by the BIOS. I have another of the same hd, so I exchanged the boards. I found out that there is a problem on its board since my good hd didn't work. But the broken hd doesn't work with the good board as well: it can be recognized but when I insert a Windows Instalation DVD it says the hd is 0GB. I put it in a case and use it in another computer via USB, and but it doesn't show up in the "My Computer". I used a software to recover files called "GetDataBack for NTFS", it recognized the hd but with the wrong size (2TB). I try to make it read the hd but it get an I/O error reading sector. It tries to read, the hd spins... So, since I'm using a good board on it, the problem seems to be internal. Is there anything someone could do recover the files from it?

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  • Can't log into Windows XP

    - by lamcro
    Immediately after choosing an account, and starting to log in, it shows the logging out message and goes back to the account selection display. This even happened in safe mode with the administrator's account. So I can't log in. I'll be using a Linux Live CD to extract the laptop's data. Could this be a virus or a hard disk problem? And what should I do?

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  • How to fix windows 7 boot process

    - by MasterCorban
    Ok so i used xp for years before i was able to get my hands on the Windows7 RC which i bought a new HDD for, and then followed the process to dual-boot. About a month ago xp started acting funny and i thought the disk might be dying. So i started using Windows7 all the time. Today i start the computer and it cant find the disk which xp was on anymore. I guess its dead. So i remove the xp HD and my computer cant start...insert bootable disk or something similar So how can i remove the primary(dead) xp disk and boot straight to Windows 7?

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  • I suspect that my HDD is causing hardlocks, as all other components have been replaced. How can I check this theory and solve the potential cause?

    - by user867814
    I have had this problem over quite a while now, thorough multiple Linux kernel versions and distributions, as well as replacement of all components, aside from my main HDD - RAM, GPU(twice), mother board, CPU, power supply. What happens is, at one point during the operation of the PC, it will hardlock - everything stops working, external HDD is not shut down correctly and continues to spin until I plug it out and in, there are no system/kernel logs of any kind, and no otherwise nothing that would suggest a cause. Another reason for my suspicion is that the failures happen almost exclusively during HDD read/write activity - shutdown(happens nearly 1/3 of the time so far, it's only been few days though), launching programs, and once during operation of apt. I hope the post is descriptive enough, if you need any additional info, ask(and tell me how to prepare/obtain it), and I will provide. If I'm wrong, point me in the right direction. Thanks in advance.

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  • How to force a hard drive to shut down

    - by Phenom
    I have a hard drive in my computer that I'm not using. I want Windows 7 to shut it down. I don't want to have to manually remove the cable. (The reason is that for some strange reason my computer will not boot if it's not connected. disk boot failure after upgrading power supply) I know that Windows 7 will shut it down after a certain period of time of it not being used. How can I force it to shut down without having to wait for this?

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  • Cheap NAS for connecting a USB drive to the network

    - by olaeld
    I am looking for a cheap way of hooking up a USB drive to the LAN. This could be a router with a USB port, or possibly a more regular NAS device with a USB port. I am hoping to find something below $200. But if there is a device with "magical properties" I may be interested to hear about it anyway.

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  • Tool to test HDD for health?

    - by Ognjen
    I've had my HDD replaced, and now my computer is freezing every 1 to 5 minutes for 5 to 10 seconds. Actually, only active applications freeze (but it can be ANY application), usually when I click something, but sometimes by themselves. How can I check if this is HDD issue or software issue? I don't want to send my laptop for second HDD replacement right away, since the last service took 40 days, so I am looking for a tool that could confirm that this is a HDD issue.

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  • Why will multiple dvd/cd-rom drives stop reading?

    - by ddc0660
    I'm having difficulty with two dvd/cd drives. When I updated from XP to Vista, I noticed they wouldn't work. I could add cds or dvds to the drives and they would attempt to read the disk, but never "found" a disk in the drive. Vista showed the drives existed without problems. I updated their drivers and nothing changed. I thought perhaps, oddly, both drives were going bad. Then I got Windows 7, and I figured I'd have to do some gymnastics in order to get it onto my system without a working disk drive. However, I can boot from the Windows 7 disk fine! I installed 7 hoping that it was a Vista problem and I'd reclaim my drives, but that is not the case. The same symptoms persist. Thoughts?

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  • Windows Defender Update KB915597 (Definition 1.135.415.0)? Killed My Live Discs

    - by user88311
    Here's my problem, for those willing to read for about 2 minutes here's the entire story, http://answers.microsoft.com/en-us/windows/forum/windows_vista-windows_update/bsod-after-windows-defender-update-kb915597/a4b5fca3-0274-47b4-97c4-61b34c4c4599, for those who want the short version here's what happened. After windows update automatically updated windows defender to kb915597, my computer starting getting bsods on shut down and start up and started experiencing problems withe the usb ports. So I decided to go to the microsoft answers site for help, I know that was probably my first mistake, so I followed their advice and they turned my computer into a large paper weight. Luckily I make physical backups of my c drive every few months and I have one from back in july, so I figured I'd boot up a ubuntu live disc, copy all my files from the past 2 months to a external drive and just copy the backup back to the c drive, that's where I ran into this problem. When I put in either a ubuntu or kubuntu disc, everything goes well, until it finishes the loading bar then when the OS would presumably start up, the computer resets, I've tried with ubuntu, kubuntu and gparted, and only gparted is able to get to the point where it starts up, but even then when I try to access the internet from it, the computer resets, and when I tried to copy the entire C drive partition to a blank external I wasn't able to. So I figured somehow maybe the C drive had something to do with it, so I unplugged the C drive so my computer was just a 2.8 ghz processor and 2 gigs of ram, should have had no problem starting a live disc but the problem still continues. After doing some googling around I've found whenever windows gets a update with the title KB915597 it's pretty much the kill switch for windows, I've tried contacting microsoft tech support and even managed to directly contact a software engineer but as soon as I mention KB915597 they all just blew me off. I hope anybody who reads this has any idea how to fix this, I'm going to attempt to install ubuntu or kubuntu to a external drive using the same computer and see what happens now.

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  • New SSD, is the MBR broken? DISK BOOT FAILURE

    - by Shevek
    I've been running Windows 7 on a WD 500gb SATA single drive, single partition setup for some time with no issues. I've just installed a new Kingston V Series 64gb SSD and performed a clean install of Win7 to it, deleting the partitions on the 500gb and using that as a data drive. All was well for a few reboots but then I started to get "DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER" messages. If I put the Win7 install DVD back in the drive it boots fine. Tried a clean install again, after replacing SATA cables and swapping SATA ports, with a complete partition wipe of both drives. Again, rebooted fine a few times then back with the "DISK BOOT FAILURE" error. Looked on the web and found some discussions about it so I then started from scratch again. This time I wiped the MBR on both drives using MBRWork, disconnected the 500gb and reinstalled to the SSD. Removed the install DVD and installed all the drivers which involved many reboots, all with no problem. To make sure I also did a few cold boots as well. Reconnected the 500gb, initialised, partitioned and formatted it. Copied data to it and did some more reboots and shutdowns. All was ok. Then out of the blue comes another "DISK BOOT FAILURE" and again, if the Win7 install DVD is in the drive it boots fine. So, is the SSD a bad'un? TIA UPDATE: It was a BIOS issue! I found a hidden away option for HDD boot order, which was separate from the usual HDD/CDRom/FDD boot order option. The WD was set to boot before the SSD... Swapped them round and all is well. Still don't understand how it worked at first though... Thanks Solaris

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  • Turn A Flash Drive Into a Portable Web Server

    - by Matthew Guay
    Portable applications are very useful for getting work done on the go, but how about portable servers?  Here’s how you can turn your flash drive into a portable web server. Getting Started To put a full web server on our flash drive, we’re going to use XAMPP Lite.  This lightweight, preconfigured server includes recent versions of Apache, MySQL, and PHP so you can run most websites and webapps directly from it.  You could use the full XAMPP, which includes more features such as a FileZilla FTP server and OpenSSL, but for most purposes, the light version is plenty for a portable server. Download the latest version of XAMPP Lite (link below).  In this tutorial, we used the self-extracting EXE version; you could choose the ZIP file and extract the files yourself, but we found it easier to use the executable. Run the installer, and click Browse choose where to install your server. Select your flash drive, or a folder in it, and click Ok.  Make sure your flash drive has at least 250MB of available storage space.  XAMPP will create an xampplite folder and store all the files in it during the installation.   Click Install, and all of the files will be extracted to your flash drive.  This may take a few moments depending on your flash drive’s speed. When the extraction process is finished, a Command Prompt window will open to finish the installation.  The first prompt will ask if you want to add shortcuts to the start menu and desktop; enter “n” since we don’t want to create start menu links to our portable server. Now enter “y” to configure XAMPP’s directories automatically. Finally, enter “y” to make XAMPP fully portable.  It will set up the servers to run without specific drive letters so your server will run from any computer. XAMPP will finalize your changes; press Enter when everything is completed. Setup will automatically launch the command line version of XAMPP.  On first run, confirm that your time zone is correct. And that’s it!  You can now run XAMPP’s control panel by entering 1, or you can exit and run XAMPP from any other computer with your flash drive. To complete your portable webserver kit, you may want to install Portable Firefox or Iron Browser on your flash drive so you always have your favorite browser ready to use. Running your portable server Using your portable server is very simple.  Open the xampplite folder on your flash drive and launch xampp-control.exe. Click Start beside Apache and MySql to get your webserver running. Please note: Do not check the Svc box, as this will run the server as a Windows service.  To keep XAMPP portable, you do not want it running as a service! Windows Firewall may prompt you that it blocked the server; click Allow access to let your server run. Once they’re running, you can click Admin to open the default XAMPP admin page running from your local webserver.  Or, you can view it by browsing to http://localhost/ or http://127.0.0.1/ in your browser. If everything is working correctly, you should see this page in your browser.  Choose your default language… And then you’ll see the default XAMPP admin page.   Click the Status link on the left sidebar to make sure everything is running correctly. If you click the Admin button for MySql in the XAMPP Control Panel, it will open phpMyAdmin in your default browser.  Alternately, you can open the MySql admin page by entering http://localhost/phpmyadmin/ or http://127.0.0.1/phpmyadmin/ in your favorite browser. Now you can add your own webpages to your webserver.  Save all of your web files in the \xampplight\htdocs\ folder on your flash drive. Install WordPress in your portable server Since XAMPP Lite includes MySql and PHP, you can even run webapps such as WordPress, the popular CMS and blogging platform.  Download WordPress (link below), and extract the files to the \xampplite\htdocs folder on your flash drive. Now all of the WordPress files are stored in \xampplite\htdocs\wordpress on your flash drive. We still need to setup WordPress on our portable server.  Open your MySql admin page http://localhost/phpmyadmin/ to create a new database for WordPress.  Enter a name for your database in the “Create new database” box, and click Create. Click the Privileges tab on the top, and the select “Add a new User”.   Enter a username and password for the database, and then click the Go button on the bottom of the page. Using WordPress Now, in your browser, enter http://localhost/wordpress/wp-admin/install.php.  Click Create a Configuration File to continue. Make sure you have your Database name, username, and password we created previously, and click “Let’s Go!” Enter your WordPress database name, username, and password, leave the other two entries as default, and click Submit. You should now have the database all ready to go.  Click “Run the install” to finish installing WordPress. Enter a title, username, and password for your test blog, as well as your email address, and then click “Install WordPress”. You now have a portable install of WordPress.  Click “Log In” to  access your WordPress admin page. Enter your username and password, and click Log In. Here you can add pages, posts, themes, extensions, and anything else just like you would on a normal WordPress site.  This is a great way to experiment with WordPress without messing up your real website. You can view your portable WordPress site by entering http://localhost/wordpress/ in your address bar. Closing your server When you’re done running your test server, click the Stop button on each of the services and then click the Exit button in the XAMPP control panel.  If you press the exit button on the top of the window, it will just minimize the control panel to the tray.   Alternately, you can shutdown your server by running xampp_stop.exe from your xampplite folder. Conclusion XAMPP Lite gives you a great way to run a full webserver directly from your flash drive.  Now, anywhere you go, you can test and tweak your webpages and webapps from any Windows computer.  Links Download XAMPP Lite Download WordPress Similar Articles Productive Geek Tips BitLocker To Go Encrypts Portable Flash Drives in Windows 7How To Use BitLocker on Drives without TPMSpeed up Your Windows Vista Computer with ReadyBoostView and Manage Flash Cookies the Easy WayInstall and Run Applications from Your iPod, Flash Drive or Mp3 Player TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 OutlookStatView Scans and Displays General Usage Statistics How to Add Exceptions to the Windows Firewall Office 2010 reviewed in depth by Ed Bott FoxClocks adds World Times in your Statusbar (Firefox) Have Fun Editing Photo Editing with Citrify Outlook Connector Upgrade Error

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  • Must partprobe before using drive?

    - by Jeff Welling
    This is a followup question to Cannot mount /dev/sdc1 on Debian 5.0, special device /dev/sdc1 doesn't exist Basically, I have 6 SATA hard drives in a machine and I'm trying to create a RAID6 array with them. When I try to run the mdadm command to create (with the verbose option) a raid array, I see messages like "mdadm: super1.x cannot open /dev/sdf1: No such device or address" which are resolved by doing partprobe /dev/sdf and then re-running the mdadm command. The problem is that I have to run partprobe after each reboot, and from experience I don't think this is normal behaviour -- on no other linux machine do I have to partprobe the device before I can use it. Something must be going wrong, but how do I troubleshoot this to find out what? Could this be caused by a hardware problem? Edit: Additional note - before I seemed to only have this problem with one drive, but now I'm having it with 3 drives.

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  • DVD-RW Drive not recognizing a DVD+R disc

    - by unknown (yahoo)
    Hi everyone, I am having trouble burning DVD+R disc's. My OS is vista and i have used this burner and these same discs in the past. I haven't had the need to do so in months and now that i come back to create some backups my DVD/RW drive doesn't recognize a brand new DVD+R disc. These disc are the same ones i have used in the past(Same Pack even). Anyone have any idea what this might be. Maybe a vista upgrade or something that i downloaded in the last few months that could have thrown something off? Thanks in advance.

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  • jump to page of a pdf in google docs / drive / apps

    - by Aaron - Solution Evangelist
    i want to jump to a specific page of a pdf file via the google docs via the editor url https://docs.google.com/file/d/xxx/edit or the embed url https://docs.google.com/file/d/xxx/preview i am not looking to use the http://docs.google.com/gview?url= referenced in the stackoverflow question how to open specific page on Google's docs viewer as i want to do this for documents where authentication is required the the document is not available via public url. is there some way of appending an anchor (i would have expected it to be https://docs.google.com/file/d/xxx/preview#10) or a query (e.g. https://docs.google.com/file/d/xxx/preview?page=10) to the google docs / drive / apps viewer?

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  • User's home drive permissions don't contain system or administrators on Windows Server 2008 R2

    - by JohnyV
    I have a user whose home drive has only that user in the permissions. No administrators, etc. I have tried to take ownership as a local administrator however I cant seem to apply settings to the child objects -- it still gives me a permission denied error. I know there are some handy CLI utils that can redo permissions. Any ideas? Or even a way to do it through Windows? The file server is a 2008 R2 server.

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  • Win 2008 R2 Server Not Recognizing Second Hard Drive

    - by Brian
    Hello, I just purchased a Dell server, which has two hard drives and no RAID setup. I can only currently see one hard drive... not sure how to get it to recognize the other, as I thought being a new machine that wouldn't be an issue. It has Windows Server 2008 R2 that I loaded on. I'm a n00b to all of this so I'm not sure why this is failing to work... Any help appreciated. Thanks.

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  • Windows XP loses drive letter for existing partition on disk

    - by Kev
    Hi, apologies if this has already been asked - I couldn't spot anything exactly the same. I'm looking for help on the fact that Windows XP has suddenly decided to stop assigning a drive letter to the second partition on my laptop's disk. I haven't added or changed hardware and I keep everything pretty clean in terms of software installed. I've partitioned the disk into a system partition on C: and a user partition on d: but lately, when booting or coming out of hibernation or sometime from stand-by, Windows will lose it's d: mapping. If I notice and remap it from MMC, everything will be perfectly happy and will keep going. Any help on this will be greatly appreciated. Cheers, Kev

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  • Video games, content strategy, and failure - oh my.

    - by Roger Hart
    Last night was the CS London group's event Content Strategy, Manhattan Style. Yes, it's a terrible title, feeling like a self-conscious grasp for chic, sadly commensurate with the venue. Fortunately, this was not commensurate with the event itself, which was lively, relevant, and engaging. Although mostly if you're a consultant. This is a strong strain in current content strategy discourse, and I think we're going to see it remedied quite soon. Not least in Paris on Friday. A lot of the bloggers, speakers, and commentators in the sphere are consultants, or part of agencies and other consulting organisations. A lot of the talk is about how you sell content strategy to your clients. This is completely acceptable. Of course it is. And it's actually useful if that's something you regularly have to do. To an extent, it's even portable to those of us who have to sell content strategy within an organisation. We're still competing for credibility and resource. What we're doing less is living in the beginning of a project. This was touched on by Jeffrey MacIntyre (albeit in a your-clients kind of a way) who described "the day two problem". Companies, he suggested, build websites for launch day, and forget about the need for them to be ongoing entities. Consultants, agencies, or even internal folks on short projects will live through Day Two quite often: the trainwreck moment where somebody realises that even if the content is right (which it often isn't), and on time (which it often isn't), it'll be redundant, outdated, or inaccurate by the end of the week/month/fickle social media attention cycle. The thing about living through a lot of Day Two is that you see a lot of failure. Nothing succeeds like failure? Failure is good. When it's structured right, it's an awesome tool for learning - that's kind of how video games work. I'm chewing over a whole blog post about this, but basically in game-like learning, you try, fail, go round the loop again. Success eventually yields joy. It's a relatively well-known phenomenon. It works best when that failing step is acutely felt, but extremely inexpensive. Dying in Portal is highly frustrating and surprisingly characterful, but the save-points are well designed and the reload unintrusive. The barrier to re-entry into the loop is very low, as is the cost of your failure out in meatspace. So it's easy (and fun) to learn. Yeah, spot the difference with business failure. As an external content strategist, you get to rock up with a big old folder full of other companies' Day Two (and ongoing day two hundred) failures. You can't send the client round the learning loop - although you may well be there because they've been round it once - but you can show other people's round trip. It's not as compelling, but it's not bad. What about internal content strategists? We can still point to things that are wrong, and there are some very compelling tools at our disposal - content inventories, user testing, and analytics, for instance. But if we're picking up big organically sprawling legacy content, Day Two may well be a distant memory, and the felt experience of web content failure is unlikely to be immediate to many people in the organisation. What to do? My hunch here is that the first task is to create something immediate and felt, but that it probably needs to be a success. Something quickly doable and visible - a content problem solved with a measurable business result. Now, that's a tall order; but scrape of the "quickly" and it's the whole reason we're here. At Red Gate, I've started with the text book fear and passion introduction to content strategy. In fact, I just typo'd that as "contempt strategy", and it isn't a bad description. Yelling "look at this, our website is rubbish!" gets you the initial attention, but it doesn't make you many friends. And if you don't produce something pretty sharp-ish, it's easy to lose the momentum you built up for change. The first thing I've done - after the visual content inventory - is to delete a bunch of stuff. About 70% of the SQL Compare web content has gone, in fact. This is a really, really cheap operation. It's visible, and it's powerful. It's cheap because you don't have to create any new content. It's not free, however, because you do have to validate your deletions. This means analytics, actually reading that content, and talking to people whose business purposes that content has to serve. If nobody outside the company uses it, and nobody inside the company thinks they ought to, that's a no-brainer for the delete list. The payoff here is twofold. There's the nebulous hard-to-illustrate "bad content does user experience and brand damage" argument; and there's the "nobody has to spend time (money) maintaining this now" argument. One or both are easily felt, and the second at least should be measurable. But that's just one approach, and I'd be interested to hear from any other internal content strategy folks about how they get buy-in, maintain momentum, and generally get things done.

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  • Cost Comparison Hard Disk Drive to Solid State Drive on Price per Gigabyte - dispelling a myth!

    - by tonyrogerson
    It is often said that Hard Disk Drive storage is significantly cheaper per GiByte than Solid State Devices – this is wholly inaccurate within the database space. People need to look at the cost of the complete solution and not just a single component part in isolation to what is really required to meet the business requirement. Buying a single Hitachi Ultrastar 600GB 3.5” SAS 15Krpm hard disk drive will cost approximately £239.60 (http://scan.co.uk, 22nd March 2012) compared to an OCZ 600GB Z-Drive R4 CM84 PCIe costing £2,316.54 (http://scan.co.uk, 22nd March 2012); I’ve not included FusionIO ioDrive because there is no public pricing available for it – something I never understand and personally when companies do this I immediately think what are they hiding, luckily in FusionIO’s case the product is proven though is expensive compared to OCZ enterprise offerings. On the face of it the single 15Krpm hard disk has a price per GB of £0.39, the SSD £3.86; this is what you will see in the press and this is what sales people will use in comparing the two technologies – do not be fooled by this bullshit people! What is the requirement? The requirement is the database will have a static size of 400GB kept static through archiving so growth and trim will balance the database size, the client requires resilience, there will be several hundred call centre staff querying the database where queries will read a small amount of data but there will be no hot spot in the data so the randomness will come across the entire 400GB of the database, estimates predict that the IOps required will be approximately 4,000IOps at peak times, because it’s a call centre system the IO latency is important and must remain below 5ms per IO. The balance between read and write is 70% read, 30% write. The requirement is now defined and we have three of the most important pieces of the puzzle – space required, estimated IOps and maximum latency per IO. Something to consider with regard SQL Server; write activity requires synchronous IO to the storage media specifically the transaction log; that means the write thread will wait until the IO is completed and hardened off until the thread can continue execution, the requirement has stated that 30% of the system activity will be write so we can expect a high amount of synchronous activity. The hardware solution needs to be defined; two possible solutions: hard disk or solid state based; the real question now is how many hard disks are required to achieve the IO throughput, the latency and resilience, ditto for the solid state. Hard Drive solution On a test on an HP DL380, P410i controller using IOMeter against a single 15Krpm 146GB SAS drive, the throughput given on a transfer size of 8KiB against a 40GiB file on a freshly formatted disk where the partition is the only partition on the disk thus the 40GiB file is on the outer edge of the drive so more sectors can be read before head movement is required: For 100% sequential IO at a queue depth of 16 with 8 worker threads 43,537 IOps at an average latency of 2.93ms (340 MiB/s), for 100% random IO at the same queue depth and worker threads 3,733 IOps at an average latency of 34.06ms (34 MiB/s). The same test was done on the same disk but the test file was 130GiB: For 100% sequential IO at a queue depth of 16 with 8 worker threads 43,537 IOps at an average latency of 2.93ms (340 MiB/s), for 100% random IO at the same queue depth and worker threads 528 IOps at an average latency of 217.49ms (4 MiB/s). From the result it is clear random performance gets worse as the disk fills up – I’m currently writing an article on short stroking which will cover this in detail. Given the work load is random in nature looking at the random performance of the single drive when only 40 GiB of the 146 GB is used gives near the IOps required but the latency is way out. Luckily I have tested 6 x 15Krpm 146GB SAS 15Krpm drives in a RAID 0 using the same test methodology, for the same test above on a 130 GiB for each drive added the performance boost is near linear, for each drive added throughput goes up by 5 MiB/sec, IOps by 700 IOps and latency reducing nearly 50% per drive added (172 ms, 94 ms, 65 ms, 47 ms, 37 ms, 30 ms). This is because the same 130GiB is spread out more as you add drives 130 / 1, 130 / 2, 130 / 3 etc. so implicit short stroking is occurring because there is less file on each drive so less head movement required. The best latency is still 30 ms but we have the IOps required now, but that’s on a 130GiB file and not the 400GiB we need. Some reality check here: a) the drive randomness is more likely to be 50/50 and not a full 100% but the above has highlighted the effect randomness has on the drive and the more a drive fills with data the worse the effect. For argument sake let us assume that for the given workload we need 8 disks to do the job, for resilience reasons we will need 16 because we need to RAID 1+0 them in order to get the throughput and the resilience, RAID 5 would degrade performance. Cost for hard drives: 16 x £239.60 = £3,833.60 For the hard drives we will need disk controllers and a separate external disk array because the likelihood is that the server itself won’t take the drives, a quick spec off DELL for a PowerVault MD1220 which gives the dual pathing with 16 disks 146GB 15Krpm 2.5” disks is priced at £7,438.00, note its probably more once we had two controller cards to sit in the server in, racking etc. Minimum cost taking the DELL quote as an example is therefore: {Cost of Hardware} / {Storage Required} £7,438.60 / 400 = £18.595 per GB £18.59 per GiB is a far cry from the £0.39 we had been told by the salesman and the myth. Yes, the storage array is composed of 16 x 146 disks in RAID 10 (therefore 8 usable) giving an effective usable storage availability of 1168GB but the actual storage requirement is only 400 and the extra disks have had to be purchased to get the  IOps up. Solid State Drive solution A single card significantly exceeds the IOps and latency required, for resilience two will be required. ( £2,316.54 * 2 ) / 400 = £11.58 per GB With the SSD solution only two PCIe sockets are required, no external disk units, no additional controllers, no redundant controllers etc. Conclusion I hope by showing you an example that the myth that hard disk drives are cheaper per GiB than Solid State has now been dispelled - £11.58 per GB for SSD compared to £18.59 for Hard Disk. I’ve not even touched on the running costs, compare the costs of running 18 hard disks, that’s a lot of heat and power compared to two PCIe cards!Just a quick note: I've left a fair amount of information out due to this being a blog! If in doubt, email me :)I'll also deal with the myth that SSD's wear out at a later date as well - that's just way over done still, yes, 5 years ago, but now - no.

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